1. Field
The present application relates generally to the operation of broadcast networks, and more particularly, to methods and apparatus for improved DVB network information acquisition.
2. Background
Transport streams in a Digital Video Broadcast (DVB) network employ a construct known as an IP/MAC Notification Table (INT) as part of Program Specific Information/Service Information signaling. Essentially, the INT provides a flexible address resolution mechanism to locate IP/MAC streams within a DVB network. The address resolution is achieved by providing a mapping of (a range of) IP/MAC addresses to a corresponding stream location where the stream location is given in the form of a network identifier (ID), original network ID, transport stream ID, service ID and component tag. The IP/MAC addresses are scoped by an IP/MAC platform. The IP/MAC platform represents a harmonized IP/MAC address space, i.e., one without any address conflicts. An IP/MAC platform may span several transport streams within one or multiple networks. Conversely, a transport stream or a network may contain more than one IP/MAC platforms.
A DVB receiver needs to acquire sufficient network information so that it can translate the above stream locations into physical layer parameters (frequency, modulation, etc.). The network information is carried in a Network Information Table (NIT)—Actual and a Network Information Table—Other. On a given transport stream, the NIT-Actual carries network information of the network to which the transport stream belongs while the NIT-Other carries information on other networks. Transmission of the NIT-Actual is mandatory while transmission of NIT-Other is optional.
A brute force approach to acquire complete network information can be quite inefficient and time consuming. For example, since a receiver has no knowledge of which networks can be potentially referred to by stream locations in the INT, a receiving device can utilize a brute force approach by tuning to all the possible frequencies to acquire the NIT so that it has network information for all the possible networks. Additionally, if the NIT-Other is transmitted, the receiver can potentially receive the complete network information by tuning to only a subset of frequencies. However, a receiver has no a-priory knowledge about whether NIT-Other is being transmitted on a particular transport stream and the periodicity of transmission of the NIT-Other may be much higher than that of the NIT-Actual. Hence, if a receiver wishes to acquire the NIT-Other, it has to stay on a transport stream much longer to receive the NIT-Other or until a time-out occurs. This in turn may lead to very long network information acquisition times and result in an unsatisfactory user experience.
Therefore, it is desirable to have an information acquisition mechanism that operates to allow a device to acquire DVB network information in a fast and efficient manner.